Upregulation of PKC δ‐ and downregulation of PKC α‐mRNA and protein by a phorbol ester in human T84 cells

摘要

>Protein kinase C (PKC) family members are downregulated by chronic activation at the protein level in most cell types. In T84 human epithelial cells 12-O-tetradecanoyl phorbol 13-acetate (TPA) caused persistent translocation of PKC δ to the membrane compartment and a 400% increase of PKC δ-mRNA after 24 h. In contrast, PKC α protein was completely downregulated and its mRNA was decreased to 60% of control levels after 24 h. This is the first report of PKC δ-mRNA upregulation by TPA which was previously only shown for PKCβ. In view of the antimitogenic actions of PKC δ this pattern of regulation may serve to preserve growth control even in the presence of chronic cell activation.